Strategies for insulating on top of & around heat sources in attics (such as recessed light fixtures).

I have been going by the rules of the program admins in my region when it comes to how to treat heat sources in attics when preparing to insulate attics with blown-in insulation. The standard operating procedure is to "dam" around heat sources (mainly recessed light fixtures) using un-faced FG batt insulation. The damming must be at least a few inches higher than the installed depth of the blown-in insulation. The end result is that blown-in insulation does not end up covering the heat source and potentially cause a fire-related problem.

But, I have been pushing for the fabrication of "boxes" made of materials such as gypsum board or aluminum flashing so that insulation can be blown on top of & around the boxes. Any thoughts on this strategy, or other strategies you'd like to put on the table?

Replies to This Discussion

Hi Patrick, If you have looked at those dams with IR with the heat source on you know they are dumping heat like mad. Exactly what you can do should be discussed with the local code official. IMO, a proper covering that would allow a full insulation layer over it is needed. Doing such without breaking the rules, the fire codes, and electrical codes is the trick and only the AHJ can answer that. But don't apply the same solution to another district without talking to that official as each may have their own rules. Personally, I advise they replace the fixture with a IC/AT rated, but the real world needs an easier fix.

One of your arguments to present to your code official is that lights can be installed in small enclosed drop ceilings, like a kitchen drop that was created after the drywall was installed. I have not seen instructions stating that the area above has to be open to an attic and many are installed in joist cavities between floors. Logic is on the side of the Gypsum box Bob is suggesting, just need the ok to use it.

Gypsum board would be good to make the "box" out of. It's easy to work with and cheap. probably wouldn't be a bad idea to box in all of the attic electrical boxes/bathroom fans and use some foam sealer or drywall mud to seal them up.